Question: $ E = \left[\begin{array}{rrrr}3 & 4 & 3 & 4 \\ 0 & 2 & 2 & 0\end{array}\right]$ What are the dimensions of matrix $ E$ ?
The first dimension is the number of rows in the matrix. How many rows does $ E$ have? The second dimension is the number of columns in the matrix. How many columns does $ E$ have? So, $ E$ is a 2 $\times$ 4 matrix.